In communication using the orthogonal frequency-division multiplexing (OFDM) scheme, for example, a preamble used to detect and synchronize signals is added to the beginning of transmission data. If distortion occurs in the preamble due to the performance of the amplifier or the characteristics of the transmission channel, for example, the receiving end may become unable to correctly restore the subsequent data. Among amplifiers used on the transmitting end, amplifiers with a lower peak-to-average power ratio (PAPR) produce signals with less distortion. Since the PAPR rises if the sequence length of the preamble becomes longer, technology for generating a preamble with a low PAPR is being developed.
Unexamined Japanese Patent Application Publication (Translation of PCT Application) No. 2008-508803 discloses technology that generates a preamble based on a constant amplitude zero auto-correlation (CAZAC) sequence.
The preamble generated by the technology disclosed in Unexamined Japanese Patent Application Publication (Translation of PCT Application) No. 2008-508803 has a power of 2 length, and the preamble length cannot be set to an arbitrary length. The types of preambles that may be generated are also limited.